1. Technical Field
The present invention relates to an electro-optical panel, an electro-optical device, and a driving method of an electro-optical device.
2. Related Art
There is known an electrophoretic phenomenon in which charged particles dispersed in move migrate by an electric field. Further, there is known an application of this phenomenon, in which charged pigment particles disperse into dispersion liquid colored by a dye, the charged pigment particles in the colored dispersion liquid is interposed between a pair of electrodes, and the charged pigment particles migrate and stick to any one electrode of the pair of electrodes. Accordingly, there have been attempts to realize a display body (electro-optical panel) based on this phenomenon.
For example, JP-A-62-269124 discloses an electrophoretic device having a structure in which electrophoretic dispersion liquid containing two kinds of electrophoretic particles having different color tones and liquid dispersion medium is interposed between a pair of electrodes. In such an electrophoretic device, if a potential is supplied across the electrodes, the particles move in a direction of an electric field toward any one electrode of the pair of electrodes and thus a color based on a color of the particles move to a displaying surface is displayed on the observer side. That is, one of the electrodes is divided into a plurality of pixel electrodes and move of the particles toward the each pixel electrode is properly controlled. Accordingly, it is possible to display an image (pattern) corresponding to the controlled pixel electrodes.
However, such a method has a disadvantage in that it is possible to express only two kinds of color tones, such as white and black.
As for the electrophoretic device, JP-A-2000-035598 discloses a color displaying method which can display a color image as well as two kinds of color tones, such as black and white. In this method, three kinds of microcapsules, each including electrophoretic particles and a dispersion medium colored by any one of predetermined three primary colors, are arranged on a substrate in a predetermined arranging manner. The three kinds of microcapsules are discerned on the basis of colors of the dispersion media. The colors of the microcapsules are individually controlled and thus it is possible to realize a color display.
However, according to this method, it is possible to express black by performing a subtractive color process, and thus it is possible to express black having a sufficiently low reflectivity. Further, it is impossible to individually express the grayscale by every microcapsule.
JP-A-2001-290444 discloses a color correcting method which compensates a difference between a color of particles and a color of a dispersion medium.
However, this method also has a disadvantage in that it can express only two kinds of color tones and it cannot express the grayscale.
JP-T-2002-511607 discloses a method of realizing a color display. According to this method, three kinds of particles having different colors are employed and an electric field is applied in a manner such that one kind of particles of the three kinds of particles is disposed on the observer side. However, this method has a problem in that it is possible to only three kinds of color tones corresponding to colors of the particles.
JP-T-2002-511607 discloses a further method in which two kinds of particles having different colors are dispersed into dispersion media colored in different colors, respectively. This method also has a problem in that it is possible to express only three colors including two colors of the particles and a color of the dispersion medium because only one kind of color tone is expressed when both the two kinds of particles are present on the non-observer side.
According to the above-mentioned known techniques, it is impossible to display (express) more than two kinds of color tones, such as black and white, or more than three kinds of color tones, it is impossible to produce the grayscale with respect to each color, and it is impossible to display good quality black having a sufficiently low reflectivity.